In a circuit it is possible to organize interconnected resistor sets, called resistor association. The behavior of this association varies according to the connection between the resistors, and its possible types: **in series**, **in parallel** and **mixed**.

## Serial Association

Linking resistors in series means connecting them in a single path, ie:

As there is only one way for the electric current to pass through, it is maintained throughout the circuit. The potential difference between each resistor will vary according to its resistance, so that the 1st Ohm Law is obeyed, thus:

This relationship can also be obtained by circuit analysis:

Thus the potential difference between the starting and ending points of the circuit is equal to:

Analyzing this expression, since the total voltage and current intensity are maintained, it can be concluded that the total resistance is:

That is, one way to summarize and remember the properties of a series circuit is:

Stress (ddp) (U) | splits |

Current intensity (i) | is conserved |

Total resistance (R) | algebraic sum of the resistances in each resistor. |